Contact surface having a composite release layer and method of making

Abstract

A processing roll has a release layer that includes a porous rigid layer and polymer composite. The porous rigid layer may be a thermally sprayed metal that has discrete metal portions or a network of contiguous metal portions. Discrete metal from a flame sprayer may attached to each other on a contact surface to form the rigid layer. The polymer composite at least partially fills the spaces between the metal portions. The polymer composite may comprise a particulate filler, such as silica or glass beads. The release layer has good durability as the exposed surface contains both a portion that is the rigid material and a portion that is the polymer composite. This configuration enables very high release and long term durability even as the release layer wears.

What is claimed is: 
     
       1. A method of making a contact surface having a composite release layer comprising the steps of:
 a) providing a contact surface on a processing roll; 
 b) providing a rigid material; 
 c) providing a polymer composite comprising:
 i) a silicone polymer solution comprising a silicone polymer and a solvent; and 
 ii) a particulate filler dispersed within the polymer and comprising microspheres having a particle size of less than 50 μm; 
 
 d) depositing the rigid material onto the contact surface of the processing roll to produce a porous rigid layer having a thickness and comprising a plurality of rigid portions having a space there between; 
 e) depositing the polymer composite into the porous rigid layer as a liquid solution; and 
 f) scrapping an outside surface of the processing roll to remove excess polymer composite from the contact surface to produce a release layer comprising said polymer composite configured in the space between the plurality of rigid portions and an outside surface comprising:
 i) a first exposed area consisting essentially of an exposed portion of the plurality of rigid portions; and 
 ii) a second exposed area comprising the polymer composite; 
 
 
       wherein the release layer is configured on the contact surface of the processing roll. 
     
     
       2. The method of making a contact surface having a composite release layer of  claim 1 , wherein the step of depositing the rigid material on the contact surface comprises the step of flame spraying the rigid material onto the contact surface. 
     
     
       3. The method of making a contact surface having a composite release layer of  claim 1 , wherein the polymer composite further comprises a solvent comprising a hydrocarbon and wherein the silicone polymer is cured after the step of depositing the polymer composite into the porous rigid layer as a liquid solution. 
     
     
       4. The method of making a contact surface having a composite release layer of  claim 3 , wherein the solvent is a naphtha. 
     
     
       5. The method of making a contact surface having a composite release layer of  claim 1 , further comprising the step of removing a jut from the porous rigid layer. 
     
     
       6. The method of making a contact surface having a composite release layer of  claim 1 , wherein the step of depositing the polymer composite into the porous rigid layer comprises pressing the polymer composite into the porous rigid layer. 
     
     
       7. The method of making a contact surface having a composite release layer of  claim 6 , wherein the contact surface is a portion of the processing roll, and wherein the step of depositing the polymer composite into the porous rigid layer comprises pressing the polymer composite into the porous rigid layer with a doctor blade configured against the processing roll.